Full-upgrades work so well on Debian I haven't done a fresh installation in quite a long while, so my memory of the sequence of events is lacking. If package installation happens first, and configuration follows, you may be able to just ignore the Grub installation failure and finish the installation. Once done, reboot using installation media, or using Debian 11 if 12 is an addition rather than replacement, chroot into the installed system, then install and configure Grub. If if installation hasn't otherwise finished enough to make that process work, then try installing without any bootloader, and follow that with a chroot to install and configure Grub.
Statistics: Posted by mrmazda — 2024-01-25 17:29